The basic structure of an input for analog sensors may consist of a resistor that is integrated into a measuring loop and at which a voltage drop can be measured. If the resistance value is theoretically known, the current can be calculated based on the measured voltage. No monitoring measures are provided, i.e., it is not determined whether the calculated current also corresponds to the actual sensor current.
Such a structure may not make it possible to counteract variations that are, for example, temperature-related.
Especially in the field of level and pressure measurements, an exact determination of sensor values or, in other words, an exact determination of levels and pressures is very important. Faulty measurements not only may have technical effects such as overstraining of raw materials in case of an excessively high pressure. They may also be associated with other economical effects and disadvantages for the user of a sensor, i.e., a level or a pressure gauge.